The present invention relates to an apparatus for use with a sewing machine to cut a chain of stitches, trailing from a sewn garment and hold the cut chain in a predetermined location so as to be positioned to be incorporated into the leading portion of the seam of the next garment to be sewn.
Sewing machines that form seams utilizing chain stitches on a succession of pieces of material with the seam-being continued into the area intermediate the pieces of material, are well known. With seams of this type, means are provided for detaching the pieces of material one from the other by appropriate automatic chain-cutting devices after the sewn pieces have been caused to travel beyond the needle and the presser foot of the machine.
By cutting the chain of stitches with these devices, one portion of minimal length remains attached to the stitched piece of material and the other being connected to the throat plate is manipulated to a position forwardly of the needle so that it can be incorporated into the initial portion of the seam that will be formed on the next piece of material or workpiece. This procedure prevents a slackening of the seam's initial stitches which would give the leading edge of the workpiece an undesirable appearance.
The known devices for performing this function include a chain-cutting device disposed adjacent the stitch finger of the throat plate which co-operates with a chain-orienting device and gripper apparatus located forwardly the needle and usually adjacent the forward portion of the throat plate.
These apparatii suffer from the disadvantage that, because the portion of the chain to be sewn onto the next garment is located on the upper surface of the throat plate intermediate the needle hole, the gripping apparatus is frequently accidentally displaced while positioning the next workpiece in the sewing area.
The material to be sewn interferes with the chain, preventing the proper insertion of the latter into the new seam being sewn, due to the pressure and friction of the piece of material of the chain which tend to dislodge it from the gripping apparatus and move it toward the trimmer knife of the machine that is adjacently disposed, thereby hindering subsequent handling of the chain.
A sewing machine to solve these problems is disclosed in application Ser. No. 000,269, filed Jan. 2, 1987, incorporated herein by reference. In this application, a chain of stitches is sewn into the fabric. However, the sewing machine may be utilized with different sized throat plates which project a varying distance toward the gripping apparatus, and it is desirable to make adjustment in order that the gripping apparatus tightens the chain, and if the chain is loose the chain will remain longer on the gripping apparatus during the sewing of a subsequent garment, and an unsightly loose nub may be formed on the subsequent garment. Also, irrespective of the size of the throat plate, it is desirable to tighten the chain due to elasticity of the chain to prevent formation of the loose nub.
The following patents generally relate to this subject matter: U.S. Pat. Nos. 3,490,403, 4,453,481, 4,599,960, 4,599,961, 4,303,030, 4,187,793, 4,038,933, 4,149,478, 4,220,105 3,541,984, and 3,698,336, and British application No. 2,058,858.